Passengers on Southwest Airlines flights will soon be required to keep their portable chargers in plain sight while using them because of concerns about the growing number of lithium battery fires.

As of May 28, Southwest Airlines’ new charger policy is in effect. The change comes after multiple safety incidents and dozens of recalls involving overheating or exploding chargers, according to Travel and Leisure.

Southwest Airlines will introduce a new policy requiring portable chargers to be visible when they're in use onboard.